Hundreds of Shiite men in Baghdad have volunteered to join the fight against militants from the Islamic State of Iraq and the Levant (ISIL) in the north.

They gathered at the police headquarters in the Iraqi capital on Monday, chanting Shiite religious slogans.

Thousands across the country have followed the call of their spiritual leader, Grand Ayatollah Ali al-Sistani, to take up arms and “fight the enemy.”

One volunteer said: “Our leader (al-Sistani) called for Jihad and so we came for Jihad. We do not want salaries, we do not want anything. We have left everything behind us. We left our families and we came for Jihad.”

Meanwhile ISIL, who are Sunni militants, have vowed to capture Baghdad and cities further south.

Earlier the group posted photos online that appear to show mass killings of captured soldiers. The UN has called the reports “deeply disturbing”